1. How Can 2D Materials Advance Energy
Storage ?
15th Anniversary High Value Manufacturing & 4th New Materials & Graphene
Conference 2017
2-3 November 2017
www.cir-strategy.com/events
Dr M. J. Loveridge, Warwick University

2. Energy Storage Challenges - A QUADRILEMMA
BaDery uptake for grid, vehicles and
beyond has major challenges to
overcome……
>
$150/KWh 550 Wh/L 2025

3. Discharge: The Odyssey
Charge: The Iliad
Li’s “Troy” Li’s “Ithaca”
ANODE CATHODE
Li ions have perpetually tortuous, repeated voyages….

4. Li-ion anode & cathode chemistry
BaDery Innova[ons - Evolu[on Not Revolu[on
C LiCoO2
More cathode material developments have been
commercially successful (compared with anodes)

5. Material Dimensional Considera[ons
and the ra[onale behind bio-inspira[on.

6. Biological microstructures are the most op[mised and func[onal
microstructures that exist.
Why bio-inspired?
Lamella
1nm 5-20 nm 50-100 nm 3 – 7 µm 10 – 500 µm >1 cm
Osteon Mineral crystals Compact macrostructure Fiber Fibril
There are many opportuni6es to apply such structural arrangements in ba:ery components

7. Nano-structured materials for energy storage: 2D or Not 2D?
0D
1D
2D
3D
Nano Arrays
That is the ques[on…..
Intense research on
nanomaterials due to
desirable proper6es :
• SURFACE AREA
• NOVEL SIZE EFFECTS
• ENHANCED KINETICS
• MANY TAILORABLE
PROPERTIES
Advantages Disadvantages
Short diffusion
pathways, good
rate capability
Unstable and
difficult to make
High capacity,
strain relaxa6on,
rate, electrical
connec6vity
Low surface area
& diffusion rate,
scalable
manufacture
Small crystalline
size, high surface
area, large SA:V,
ease of synthesis
Energy density
limits, SEI
Large SA:V, high
capacity,
structural stability
SEI

8. Property Advantages of 2D Materials
Large surface areas and interlayer spaces of 2D materials e.g.
graphene & transi6on metal dichalcogenides (TMDs) provide an
ideal framework to store lithium (or sodium) ions electrochemically
Layered transi6on metal sulphides e.g. MoS2 have weak interplanar
bonding (van der Waals interac6ons) – Li ions can be inserted and
accommodated with less severe volume expansion

9. 2D into
Energy Innova[on Centre
Materials & Electrochemistry Group
3D

10. AMorpheus
(EPSRC)
2D Alloys
AtMoS2pheric
(EPSRC)
2D Graphene Composites
Amorphous Si-Sn anodes
MoS2-graphene hybrids
2D-3D Anode Developments for Li & Na-ion Energy Storage

11. AMorpheus – Plasma enhanced CVD SnSi NWs
Silane Vapour-Liquid-Solid Growth Mechanism
Metal current collector
2D Sn-Si hybrid NW BoDom-up NW growth

12. Versa[lity of Coa[ng 3d Substrate Current Collectors
SnSi-NWs on carbon fibres SnSi-NWs on copper foil
Uniform thickness for Li-diffusion
Prac[cal Film Thickness for energy density

13. Crystalline & Amorphous 2D Nanowires
20 30 40 50 60 70 80 90 100
0
2k
4k
6k
8k
10k
(132)(112)(031)
(220)
(011)
(020)
(220)
(422)
(333)
(111)
Intensity(a.u.)
2θ (deg)
Cubic & Tetragonal phases

14. Integra6ng 2D Materials
Fellowship: AtMoS2pheric

15. Ammonium molybdate
& Thiourea
220oC, 40 bar
(110) Basal
plane
Edge
plane
Method 1

16. Li-ion Energy Storage Na-ion Energy Storage

17. 2 µm
1 µm
Few Layer
Graphene
With
hydrothermally
grown MoS2
platelets
300 nm
Uniform &
stable MoS2
coverage
0
5000
10000
15000
20000
25000
30000
8 18 28 38 48 58 68
Intensity
2θ
MoS2 on graphene
002 MoS2
Graphene
101 MoS2
103 MoS2 110 MoS2
Method 2

18. 2D Material as mul6-func6onal
Enhancing Addi6ve
Silicon Anode Research

19. Si-graphene Composite Microstructures
Cu foil
0
500
1000
1500
2000
0 50 100 150 200 250
Specific Capacity (mAh/g)
Cycle Number
Charge-discharge Electrochemical Cycling
Few-layer
graphene
Si
Si
Cu foil current collector

20. Graphene: Holis[c Performance-enhancing Substance!
GRAPHENE
Tensile
Proper[es
Reversible Li+
Intercala[on
Improves
structural
stability
X-Y Electrical
conduc[vity
Wide spectrum of
chemical
func[onalisa[on
In-plane thermal
conduc[on Maintains
low series
resistance

21. Conclusions
Integra6ng select 2D Li host materials into 3D morphologies is
beneficial to electrochemical performance (surface area, diffusion
paths…)
Composite 2D-3D microstructures incorpora6ng graphene offer
mul6ple func6ons in energy storage systems
Recommenda[on: There is a need to explore advanced
manufacturing methodology for nanostructured materials.

22. Thank you for listening….. Any Ques[ons?
“When you step into an
intersection of fields,
disciplines, or cultures, you
can combine existing
concepts into a large number
of extraordinary new ideas.”
The Medici Effect
(relevant to energy storage innova[ons)
POSSIBILITY ZONE RISK ZONE COMFORT
ZONE
Learning
Possibili6es
The Medici Effect
Change
perspec6ve
Field value
networks
Chain of
Dependence
Assump6on
reversal

23. Mul[-scale materials for op[mised microstructures
(1) Ac[ve Materials (2) Matrix of Conduc[ve
Addi[ves
(3) Polymer Func[onality
& Hybrids
Carbon
black
CNTs
VGCF
FLG
µm clusters of
nm par[cles Configura[on /
Property
combina[ons
Branching +
chemistry
modifica[ons for
max. interac[ons
Hybrid
combina[ons
Composites
Cross-linking
with Mx+ ions